# How to compare two estimates?

I have determined the volume of multiple objects via two different methods.

I would like to express, per object, something like the percent error:

$$\delta = \frac{|V - V_{approx}|}{V} \cdot 100$$

However, I do not know the true value $$V$$, only two estimates. Therefore I was wondering what method I should use for this.

• This is a central and possibly the main point of statistics, that the true value of the parameter is unknown. Evaluating this error is hence another statistical problem, which is of lesser interest (since it is a random quantity) than the average error or the variability of the estimation. Bootstrap is a default approach to the problem. Having two methods does not really help in that using both mixes the variability between and the randomnesswithin and the dependence between both. – Xi'an Aug 10 '20 at 8:32